“We write to express our alarm at recent reports that your company is distributing anti-union materials to Whole Foods managers that directs and encourages potentially illegal interference with the rights of thousands of workers.”

After a leaked training video provided a rare glimpse into the aggressive tactics Amazon deploys to prevent its workers from organizing and bargaining for better working conditions, Sens. Elizabeth Warren (D-Mass.) and Bernie Sanders (I-Vt.) sent a letter to CEO Jeff Bezos on Wednesday expressing alarm at his trillion-dollar company’s “potentially illegal anti-union behavior” and demanding a copy of the full video.